Liquid crystal device, liquid crystal device manufacturing method, and electronic apparatus

ABSTRACT

A liquid crystal device comprises a plurality of pixel electrodes ( 6 ), and nonlinear elements ( 11 ) including element-side electrodes ( 14 ) electrically connected to the pixel electrodes ( 6 ). An element-side electrode ( 14 ) is shaped in a pattern ( 14   a ) formed along the edge of a pixel electrode ( 6 ). The presence of the element-side electrode pattern ( 14   a ) makes it possible to prevent etchant from entering between said pixel electrode ( 6 ) and the element-side electrode ( 14 ) and causing a wire break therebetween in patterning the pixel electrode ( 6 ). When the element-side electrode pattern ( 14   a ) is made of a substance having a higher light-shielding ability than that of the pixel electrode ( 6 ), it may be used as a mark for adjusting position in bonding an element substrate and an opposite substrate.

TECHNICAL FIELD

[0001] The present invention relates to a liquid crystal device thatdisplays visible images, such as letters and numbers, by controlling thealignment of liquid crystal to modulate light. The present inventionalso relates to an electronic apparatus including the liquid crystaldevice. The present invention further relates to a manufacturing methodof manufacturing such a liquid crystal device.

BACKGROUND ART

[0002] (1) In recent years, a liquid crystal device has found use as avisible image display part in various types of electronic apparatuses,such as a car navigation system, and a portable electronic terminal. Ina well-known type of liquid crystal device, a plurality of pairs ofpixel electrodes and nonlinear elements are formed on an elementsubstrate, opposite electrodes, and a color filter as needed, are formedon an opposite substrate, the element substrate and the oppositesubstrate are bonded to each other, and a cell gap formed between thesubstrates is sealed with liquid crystal.

[0003] Consideration will now be given to a liquid crystal device usinga MIM (Metal Insulator Metal) element that is a typical example of a TFD(Thin Film Diode) element as a nonlinear element. A pattern structureincluding the surroundings of pixel electrodes and nonlinear elementsformed on an element substrate in the liquid crystal device isconventionally formed as shown in, for example, FIG. 6. Namely, a wireline 82 and a first electrode 83 are formed on a glass substrate 81, ananodized film 84 is formed thereon, and a second electrode 86 is formedon the anodized film 84. The layered structure including the firstelectrode 83, the anodized film 84, and the second electrode 86 forms aMIM element 87 serving as a nonlinear element. A pixel electrode 88 isformed so as to overlap with the leading end of the second electrode 86in the MIM element 87.

[0004] The pixel electrode 88 is generally formed by photolithography.Specifically, first, an ITO (Indium Tin Oxide) film having a uniformthickness is formed on the glass substrate 81 by sputtering or the like,and then, an unnecessary part of the ITO is removed by etching, therebyforming the pixel electrode 88 in a desired pattern. In this case, aproblem is that gaps G are formed between the ITO film 88′ and thesecond electrode 86 in forming the ITO film on the glass substrate 81 bysputtering or the like since the part of the ITO film 88′ overlappingwith the second electrode 86 of the MIM element does not completelyadhere to the second electrode 86.

[0005] If such gaps G are produced, when etching is performed later topattern the ITO film 88′, etchant may enter the gaps G, which may causea wire break between the second electrode 86 and the pixel electrode 88.Such a wire break can cause a dot defect in a visible image display areaof the liquid crystal device. The transparent conductive film to be usedas the pixel electrode may be made of SnOx, ZnOx, or the like instead ofITO. There is a fear that these film materials will insufficientlyadhere to the second electrode 86. Therefore, a wire break may be causedby etching these materials.

[0006] (2) In general, the liquid crystal devices include anactive-matrix liquid crystal device in that nonlinear elements areprovided for respective pixels, and a passive-matrix liquid crystaldevice that does not use such nonlinear elements. In the active-matrixliquid crystal device, an element substrate having nonlinear elementsand transparent pixel electrodes and an opposite substrate havingopposite electrodes are bonded to each other, and a cell gap formedbetween the substrates is sealed with liquid crystal.

[0007] Element substrates and opposite substrates are not fabricated oneby one, and, in general, a plurality of element substrates and oppositesubstrates are formed in substrate base materials having a large area,respectively. By bonding the element substrate base material and theopposite substrate base material thus fabricated, a plurality of liquidcrystal panels are simultaneously formed. The element substrate basematerial and the opposite substrate base material are bonded such as toalign alignment marks that are formed at appropriate positions thereon.

[0008] In a conventional liquid crystal device manufacturing method, inorder to confirm whether the element substrate base material and theopposite substrate base material are bonded in a proper positionalrelationship, an image of one pixel portion in the liquid crystal panelis formed by using an image pickup device such as a CCD camera anddisplayed on a screen of a CRT monitor or the like, or one pixel portionis microscopically observed, whereby it is examined whether the bondedstate is proper from a positional point of view.

[0009] In a conventional inspection method, for example, the peripheralline of the transparent pixel electrode on the element substrate and apredetermined reference mark on the opposite substrate side, forexample, the peripheral line of an opening portion of a black matrix,are compared with each other, and it is determined whether they are in aproper positional relationship. Thereby, it is determined whether thebonded state of the element substrate and the opposite substrate is goodor bad. If it is good, the device is shipped as a product. If it is bad,the device is disposed of. Since the transparent pixel electrodes formedon the element substrate side are almost colorless and transparent,however, it is very difficult to perform a precise inspection in a shorttime in the case of the conventional liquid crystal device that issubjected to visual inspection with reference to the transparent pixelelectrodes.

[0010] (3) The present invention has been made in view of theaforementioned problems, and an object of the present invention is toimprove productivity of liquid crystal devices by providing anappropriate member on the periphery of a pixel electrode.

[0011] More specifically, a first object of the present invention is toprovide an appropriate member on the periphery of a pixel electrode soas to prevent contact failure due to etching between a nonlinear elementand the pixel electrode, and to prevent a dot defect in a visible imagedisplay area of a liquid crystal device.

[0012] A second object of the present invention is to provide anappropriate member on the periphery of a pixel electrode so as toprecisely and visually detect the amount of offset between an elementsubstrate and an opposite substrate in a short time.

DISCLOSURE OF INVENTION

[0013] (1) In order to achieve the above first object, the presentinvention provides a liquid crystal device having a plurality of pixelelectrodes and a nonlinear element including an element-side electrodeelectrically connected to the pixel electrodes, wherein the element-sideelectrode is shaped in a pattern formed along the edge of the pixelelectrode.

[0014] According to this liquid crystal device, since a part of theelement-side electrode that overlaps with the pixel electrode is shapedlike a pattern formed along the edge of the pixel electrode, whendivided pixel electrodes are formed by etching an ITO film, etchant isprevented from entering between the element-side electrode and the ITOfilm. Therefore, it is possible to prevent a wire break between theelement-side electrode and the ITO film.

[0015] (2) In the configuration mentioned above, it is preferable thatthe element-side electrode be shaped like a ring-shaped frame along theentire peripheral edge of the pixel electrode. This makes it possible torestrict the entry of etchant as much as possible, and to thereby morereliably prevent a wire break.

[0016] (3) Preferably, the outer dimensions of the element-sideelectrode are larger than that of the pixel electrode. This makes itpossible to more reliably prevent the entry of the etchant.

[0017] (4) Next, in order to achieve the above first object, the presentinvention provides an electronic apparatus including a liquid crystaldevice having the aforementioned configuration, and a control unit forcontrolling the operation of the liquid crystal device. As such anelectronic apparatus, for example, a car navigation system, a portableterminal apparatus, and other various electronic apparatuses areavailable.

[0018] (5) In order to achieve the above second object, the presentinvention provides a liquid crystal device having an element substratehaving a nonlinear element and a transparent pixel electrode on asubstrate, and an opposite substrate opposed to the device substrate,wherein the liquid crystal element comprises a mark that overlaps withat least a part of the peripheral edge of the transparent pixelelectrode in a plane manner and has a higher light-shielding abilitythan that of the transparent pixel electrode.

[0019] According to this liquid crystal device, since the mark overlapswith at least a part of the peripheral edge of the transparent pixelelectrode in a plane manner, it can be determined, by visually comparingthe mark on the element substrate and a reference mark on the oppositesubstrate, whether or not the positional relationship between theelement substrate and the opposite substrate is proper. In particular,since the mark is formed so that it has a higher light-shielding abilitythan that of the transparent pixel electrode, it is easy to visuallyrecognize. Therefore, it is possible to make a precise judgement in ashort time.

[0020] (6) In the liquid crystal device having the aforementionedconfiguration, it is preferable that the mark be formed at least at twopositions at the opposite corners of the transparent pixel electrode,and that the mark have two branch portions extending in almostperpendicular directions along two sides adjoining to the corners. Whenthe mark is formed at two positions at the opposite corners of thetransparent pixel electrode, if a predetermined region on the oppositesubstrate opposing a transparent pixel electrode, for example, anopening portion of a black matrix is offset from the transparent pixelelectrode in a vertical direction or a horizontal direction, the offsetcan be detected.

[0021] When the mark includes two branch portions along two sides of thetransparent pixel electrode that adjoin one corner, it is possible toeasily and precisely recognize the offset of the opening portion or thelike from the transparent pixel electrode both in a vertical directionand a horizontal direction.

[0022] (7) The mark may be shaped like a frame formed along the entireperipheral edge of the transparent pixel electrode. This makes itpossible to detect the offset with reference to the entire periphery ofthe transparent pixel electrode, and to thereby achieve an even easierand more precise inspection.

[0023] (8) Some liquid crystal devices have a structure in which anonlinear element is formed on an underlayer after the underlayer isformed on a substrate. This underlayer is made of, for example, tantalumoxide (TaOX), and has the functions of improving the adhesion of thenonlinear element, and the like. If the underlayer is present under thetransparent pixel electrode, however, the transparency of the pixel areais impaired. Therefore, the underlayer in the area corresponding to thetransparent pixel electrode is removed in most cases. In such a case,the peripheral edge of the removed part of the underlayer may be used asa position check mark.

[0024] (9) In the liquid crystal device of the present invention, thenonlinear element may be a two-terminal type nonlinear element. Thistwo-terminal type nonlinear element generally includes a firstelectrode, an insulating film laid on the first electrode, and a secondelectrode laid on the insulating film. When this two-terminal typenonlinear element is used, the mark may be made of the same material asthat of the first electrode or the second electrode of the two-terminaltype nonlinear element. In this case, since the mark can be formed bypatterning simultaneously with the patterning of the first electrode orthe second electrode, the working process is not complicated.

[0025] (10) In the liquid crystal device of the present invention, thenonlinear element may be a thin-film transistor element. When thisthin-film transistor element is used, the mark may be made of thematerial of one of the films for constituting the element, the film atleast having a higher light-shielding ability than that of the pixelelectrode. In this case, since the mark can be formed by patterningsimultaneously with the patterning of the film, the working process isnot complicated.

[0026] (11) In the liquid crystal device of the present invention, theoffset is detected while comparing the mark on the element substrateside and a reference mark on the opposite substrate side. In this case,various types of marks may be available as the reference mark on theopposite substrate side. For example, when a black matrix for formingdivided opening portions corresponding to pixels is formed on theopposite substrate, the peripheral edges of the black matrix openingportions may be compared with the mark. When the opposite substrate hasa color filter, the peripheral edges of respective color dots, whichconstitute the color filter, may be compared with the mark.

[0027] (12) Next, the present invention provides a liquid crystal devicemanufacturing method having the step of bonding an element substratehaving a nonlinear element and a transparent pixel electrode thereon andan opposite substrate opposed to the element substrate to each other,the liquid crystal device manufacturing method comprises the steps of(a) forming on the element substrate a mark having a higherlight-shielding ability than that of the transparent pixel electrode soas to overlap with at least a part of the peripheral edge of thetransparent pixel electrode in a plane manner, and (b) confirming withreference to the mark whether the element substrate and the oppositesubstrate are bonded in a proper positional relationship.

[0028] According to this manufacturing method, since the mark overlapswith at least a part of the peripheral edge of the transparent pixelelectrode in a plane manner, it can be determined, by visually comparingthe mark on the element substrate side and a reference mark on theopposite substrate side, whether the positional relationship between theelement substrate and the opposite substrate is proper. In particular,since the mark is formed as a mark having a higher light-shieldingability than that of the transparent pixel electrode, it is easy tovisually recognize. Therefore, it is possible to make a precisejudgement in a short time. In this manufacturing method, the peripheraledges of opening portions of a black matrix, the peripheral edges ofrespective color dots in a color filter, and the like are also availableas the reference mark on the opposite substrate side to be compared withthe mark on the element substrate side.

[0029] (13) In the aforementioned liquid crystal device manufacturingmethod, the positional relationship between the element substrate andthe opposite substrate may be checked by forming a black matrix forforming divided opening portions corresponding to pixels on the oppositesubstrate, and making positional comparison between the mark and theperipheral edges of the opening portions of the black matrix.

[0030] (14) In the aforementioned liquid crystal device manufacturingmethod, the positional relationship between the element substrate andthe opposite substrate may be checked by forming a color film includingcolor dots of a plurality of colors on the opposite substrate, andmaking positional comparison between the mark and the peripheral edgesof the color dots in the color filter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031]FIG. 1 is a plan view showing the principal part of an embodimentof a liquid crystal device according to the present invention, inparticular, the surroundings of a pixel electrode and a MIM element.

[0032]FIG. 2 is a side sectional view taken along line X-X in FIG. 1.

[0033]FIG. 3 is a partially cutaway plan view showing an embodiment ofthe liquid crystal device according to the present invention.

[0034]FIG. 4 is a plan view showing the principal part of anotherembodiment of the liquid crystal device according to the presentinvention.

[0035]FIG. 5 is a diagram showing the outward appearance and an electriccontrol system of an embodiment of an electronic apparatus according tothe present invention.

[0036]FIG. 6 is a plan view showing the principal part of an example ofa conventional liquid crystal device.

[0037]FIG. 7 is a schematic sectional view showing a step inmanufacturing the conventional element structure shown in FIG. 6, takenalong line V-V in FIG. 6.

[0038]FIG. 8 is a plan view showing the principal part of an embodimentof a liquid crystal device according to the present invention, inparticular, one pixel electrode formed in an element substrate and thesurroundings thereof.

[0039]FIG. 9 is a sectional view showing the sectional structure takenalong line Y-Y in FIG. 8.

[0040]FIG. 10 is a partially cutaway plan view of an embodiment of theliquid crystal device according to the present invention.

[0041]FIG. 11 is a plan view of an element substrate base material thatis prepared during a series of steps for constituting a manufacturingmethod of manufacturing a liquid crystal device of the presentinvention.

[0042]FIG. 12 is a plan view of an opposite substrate base material thatis prepared during the series of steps for constituting themanufacturing method of manufacturing the liquid crystal device of thepresent invention.

[0043]FIG. 13 a plan view showing the principal part of anotherembodiment of the liquid crystal device according to the presentinvention, in particular, one of pixel electrodes formed in an elementsubstrate and the surroundings thereof.

[0044]FIG. 14 is a plan view showing the principal part of a furtherembodiment of the liquid crystal device according to the presentinvention, in particular, one of pixel electrodes formed in an elementsubstrate and the surroundings thereof.

[0045]FIG. 15 is a sectional view showing the sectional structure takenalong line Z-Z in FIG. 14.

[0046]FIG. 16 is a plan view showing the principal part of a stillfurther embodiment of the liquid crystal device according to the presentinvention.

[0047]FIG. 17 is a plan view showing the neighborhood of a TFT elementin the principal part of FIG. 16.

[0048]FIG. 18 is a sectional view showing the sectional structure of theTFT element shown in FIG. 17.

[0049]FIG. 19 is a plan view showing a state of an element substratebase material shown in FIG. 16 during manufacturing.

BEST MODE FOR CARRYING OUT THE INVENTION

[0050] (First Embodiment)

[0051]FIG. 3 is a partially cutaway plan view of an embodiment of aliquid crystal device according to claim 1 of the present invention.This liquid crystal device 1 has a pair of substrates bonded to eachother by a sealing member 2 that is shaped like a rectangular ring byprinting or the like, namely, an element substrate 3 a and an oppositesubstrate 3 b.

[0052] The element substrate 3 a has a transmissive substrate 5 a madeof, for example, glass. On the surface of the transmissive substrate 5a, a plurality of line wires 4 and a plurality of transparent pixelelectrodes 6 are formed. These line wires 4 are linearly shaped, andadjoining line wires 4 are arranged in parallel with each other. Therespective pixel electrodes 6 are arranged in a line between the linewires 4, and arranged in a matrix as a whole. The respective line wires4 are electrically connected to output terminals of a liquid crystaldriving IC 7 a that is mounted on an extended portion of thetransmissive substrate 5 a.

[0053] The opposite substrate 3 b opposed to the element substrate 3 ahas a transmissive substrate 5 b made of, for example, glass. On thesurface of the transmissive substrate 5 b, a plurality of transparentopposite electrodes 8 are formed. These opposite electrodes 8 arelinearly shaped, and adjoining opposite electrodes 8 are arranged inparallel. These opposite electrodes 8 are electrically connected tooutput terminals of a liquid crystal driving IC 7 b that is mounted onan extended portion of the transmissive substrate 5 b.

[0054] Between the line wire 4 and the pixel electrode 6, a MIM element11 is formed as a nonlinear element, as shown in FIG. 1. The MIM element11 is composed of a first electrode 12 projecting from the line wire 4,an anodized film 13 formed on the first electrode 12 by anodizing, and asecond electrode 14 formed on the anodized film 13.

[0055] A leading end 14 a of the second electrode 14 is shaped like anannular frame along the entire periphery of the pixel electrode 6. Asshown in FIG. 2, the pixel electrode 6 is overlaid on the electrodeleading end 14 a. In this embodiment, the external dimensions S of theframe-like leading end 14 a of the second electrode 14 are set equal tothose of the pixel electrode 6.

[0056] The pixel electrode 6 is formed by using a known photolithographyprocess after the second electrode 14 of the MIM element 11 is formed ina predetermined shape on the transmissive substrate 5 a that constitutesthe element substrate 3 a. Specifically, an ITO film having a uniformthickness is formed on the entire transmissive substrate 5 a bysputtering, and an unnecessary part of the ITO film is removed byetching, whereby the pixel electrode 6 is shaped like a rectangle thatfits the frame shape of the leading end 14 a of the second electrode 14.

[0057] In etching the ITO film, etchant may enter the outside of theframe-like leading end 14 a of the second electrode 14, whereas it doesnot enter the inner region of the leading end 14 a that is closed due toits frame shape. Therefore, the etchant does not enter between theelectrode leading end 14 a and the pixel electrode 6, and wire breaksare thereby avoided. As a result, it is possible to manufacture a normalliquid crystal device having no dot defect.

[0058] (Second Embodiment)

[0059]FIG. 5 shows an embodiment of an electronic apparatus according toclaim 4 of the present invention. In this embodiment, a liquid crystaldevice of the present invention is used as a display part in anelectronic apparatus serving as a car navigation system. A carnavigation system is an electronic apparatus in which the position of avehicle on a map is displayed by using the GPS (Global PositioningSystem).

[0060] The car navigation system of this embodiment comprises a displaypart 70 including, for example, the liquid crystal device 1 shown inFIG. 3, a GPS control unit 66, an input device 67, and a power supply68. The input device 67 includes a GPS antenna 69 and an infrared remotecontroller 71.

[0061] The GPS control unit 66 includes a CPU (central processingdevice) 72 for executing the general control for image display, a mainmemory 73 that stores a control program to be used in performing variouscomputations, such as computations for analysis of the vehicle positionand display of a map image, a file memory 74 that stores a map datafile, and an image display circuit 76 for transmitting a driving signalfor image display to the liquid crystal display part 70. The powersupply 68 supplies electric power to the liquid crystal display part 70,and the GPS control unit 66.

[0062] (Modification)

[0063] While the present invention according to claims 1 and 4 has beendescribed in its preferred embodiments, the present invention is notlimited to the embodiments, and various modifications may be made withinthe scope of the present invention as defined in the claims.

[0064] For example, in reference to the liquid crystal device accordingto claim 1, while the leading end 14 a of the second electrode 14 in theMIM element 11 is disposed on the entire periphery of the pixelelectrode 6 in the embodiment shown in FIG. 1, it may be opened on oneside B, as shown in FIG. 4, instead of being shaped like a ring.

[0065] In this modification, the possibility that etchant may enter thesecond electrode 14 a is reduced, compared with the related art shown inFIG. 6. Therefore, it is possible to decrease the probability of wirebreaks that occur between the pixel electrode 6 and the second electrode14. When a comparison is made between the electrode leading end havingthe open portion B shown in FIG. 4 and the annular electrode leading endhaving no open portion shown in FIG. 1, the embodiment shown in FIG. 1can more reliably prevent not only the entry of etchant, but also wirebreaks.

[0066] The liquid crystal device shown in FIG. 3 uses the active matrixmethod using MIM elements and the COG (Chip On Glass) method. Of course,the present invention may be applied to liquid crystal devices usingmounting methods other than the COG method, active-matrix liquid crystaldevices using nonlinear elements other than the MIM elements, and thelike.

[0067] In reference to the electronic apparatus according to claim 4,while the present invention is applied to a car navigation system in theembodiment shown in FIG. 5, the present invention may be, of course,applied to other various electronic apparatuses, such as a portableelectronic terminal apparatus, a video camera, and an electronicnotebook.

[0068] (Third Embodiment)

[0069]FIG. 10 is a partially cutaway plan view of an embodiment of aliquid crystal device according to claim 5 of the present invention.This liquid crystal device 21 has a pair of substrates bonded to eachother by a sealing member 2 that is shaped like a rectangular ring byprinting or the like, namely, an element substrate 3 a and an oppositesubstrate 3 b.

[0070] The element substrate 3 a has a transmissive substrate 5 a madeof, for example, glass. On the surface of the transmissive substrate 5a, a plurality of wires 4 and a plurality of transparent pixelelectrodes 6 are formed. The respective wires 4 are linearly shaped, andadjoining wires are arranged in parallel with each other. The respectivepixel electrodes 6 are arranged in a line between the wires 4, andarranged in a matrix as a whole. Between each of the pixel electrodes 6and the corresponding wire 4, a MIM element 11 is formed as atwo-terminal type nonlinear element. The respective wires 4 areelectrically connected to output terminals of a IC 7 a that is mountedon an extended portion of the transmissive substrate 5 a.

[0071] The opposite substrate 3 b opposed to the element substrate 3 ahas a transmissive substrate 5 b made of, for example, glass. A colorfilter 9 is formed on the surface of the transmissive substrate 5 b, andopposite electrodes 8 are further formed on the surface of the colorfilter 9. The opposite electrodes 8 are linearly shaped, and adjoiningopposite electrodes 8 are arranged in parallel with each other. Theseopposite electrodes 8 are electrically connected to output terminals ofa liquid crystal driving IC 7 b that is mounted on an extended portionof the transmissive substrate 5 b.

[0072] The surroundings of one of the plural pixel electrodes 6 that areformed on the element substrate 3 a are observed under magnification asshown in FIG. 8. The sectional structure taken along a break line Y-Y inFIG. 8 is shown in FIG. 9. Referring to these figures, a wire 4 isformed by laying a first layer 4 a, a second layer 4 b, and a thirdlayer 4 c one on top of another. An MIM element 11 is formed by laying afirst electrode 12, an insulating layer 13, and a second electrode 14one on top of another.

[0073] The first layer 4 a of the wire 4 and the first electrode 12 ofthe MIM element 11 are both made of a conductive metal, for example, Ta(tantalum), and have a thickness of about 2000 Å. The second layer 4 bof the wire 4 and the insulating layer 13 of the MIM element 11 are bothformed of, for example, an anodized film, and have a thickness of about500 Å. The third layer 4 c of the wire 4 and the second electrode 14 ofthe MIM element 11 are both made of a conductive metal, for example, Cr(chromium). The pixel electrode 6 is made of, for example, transparentITO (Indium Tin Oxide), and is placed so that it overlaps with theleading end of the second electrode 14 of the MIM element 11 to beelectrically connected thereto.

[0074] Referring to FIG. 9, the color filter 9 formed between thetransmissive substrate 5 b and the opposite electrodes 8 in the oppositesubstrate 3 b includes color dot portions 9 c of a plurality of colors,such as R (red), G (green), and B (blue), and a black matrix 9 b formedbetween the respective color dot portions 9 c. Each of the color dotportions 9 c aligns with an opening portion K surrounded by the blackmatrix 9 b. When the element substrate 3 a and the opposite substrate 3b are bonded in a proper positional relationship, the entire region ofthe black matrix opening portion K is positioned inwardly offset fromthe peripheral edge line of the pixel electrode 6 by a distance δ, asshown in FIG. 8.

[0075] In this embodiment, two branch portions 15 a and 15 a extendingalong two sides of the pixel electrode 6 are formed at the leading endof the second electrode 14 of the MIM element 11. Moreover, two branchportions 15 b and 15 b extending along two sides of the pixel electrode6 are formed at the corner of the pixel electrode 6 that is diagonallyopposite to the second electrode 14. These branch portions 15 a and 15 bare all made of the same material as that of the second electrode 14, inthis embodiment, Cr. Cr is a material having a higher light-shieldingability than that of ITO serving as the material of the pixel electrode6. The branch portions 15 a and 15 b made of Cr function as positioncheck marks for use in detecting the offset between the black matrixopening portion K and the pixel electrode 6.

[0076] The liquid crystal device of this embodiment has theconfiguration mentioned above. Accordingly, referring to FIG. 10, theopposite electrodes 8 are selectively scanned line by line by the liquidcrystal driving IC 7 b, and simultaneously a predetermined voltage isapplied to the MIM elements of desired pixels by the liquid crystaldriving IC 7 a, whereby the alignment of liquid crystal contained in thecorresponding pixels is controlled, and a desired visible image isdisplayed in a display area V of the liquid crystal device 21. At thistime, the black matrix 9 b in FIG. 9 for shielding from light the areaexcept the opening portions K prevents extra light from leaking outside,which achieves a high-contrast display.

[0077] In order for the black matrix 9 b to show a predetermined levelof light-shielding ability, the opening portions K and the pixelelectrodes 6 need to be opposed to each other in a proper positionalrelationship. In this embodiment, the positional relationship betweeneach opening portion K and each pixel electrode 6 is checked by using apair of position check marks 15 a and 15 b that are formed at theopposite corners of the pixel electrode 6.

[0078] Specifically, for example, (1) a peripheral line L of the blackmatrix opening portion K and the branch portions 15 a and 15 b servingas position check marks are compared. If all the four branch portions 15a and 15 b are hidden by the black matrix 9 b and do not appear in theopening portion K, it is determined that the device is good. (2) If anyof the four branch portions 15 a and 15 b appears partially in theopening portion K and it does not appear entirely in the opening portionK, it is determined that the device is good. (3) If any one of the fourbranch portions 15 a and 15 b appears entirely in the opening portion K,the offset between the opening portion K and the pixel electrode 6exceeds the permitted limit, and it is determined that the device isdefective.

[0079] Examples of dimensions of the branch marks 15 a and 15 b forposition checking will be given for plain explanation. Referring to FIG.9, when a proper gap δ between the opening portion K and the pixelelectrode 6 is equal to 10 μm, a width a of the respective branch marks15 a and 15 b may be equal to 5 μm, and a distance b between therespective branch marks 15 a and 15 b and the peripheral line L of theopen portion may be equal to 5 μm. A length c of the respective branchmarks 15 a and 15 b may be equal to about 15 μm.

[0080] While one complete liquid crystal device has been describedabove, a description will be given of a manufacturing method ofmanufacturing such a liquid crystal device as follows.

[0081] First, as shown in FIG. 11, a transmissive substrate basematerial 5 a′ made of, for example, glass and having a large area isprepared, and pixel electrodes 6, MIM elements 11 and wires 4 for aplurality of liquid crystal panels are formed on the surface of thesubstrate base material 5 a′. In this embodiment, a description will begiven of a case in which four regions R each for one liquid crystalpanel are formed on the element substrate base material 5 a′, namely,four liquid crystal panels are to be obtained. The position check marks15 a and 15 b shown in FIG. 8 are formed simultaneously with theformation of the second electrode 14 (see FIG. 9) of the MIM element 11by patterning, and therefore, they do not need a special step.

[0082] An alignment film is further formed on the element substrate basematerial 5 a′ having the MIM elements 11 and the like, and is subjectedto an alignment process such as rubbing. Moreover, a sealing member 2 isformed by printing or the like around the pixel electrodes 6 in each ofthe liquid crystal panel regions R. Thus, the element substrate basematerial 3 a′ having element substrates for four liquid crystal panelsare fabricated. Numeral 2 a denotes a liquid crystal inlet for fillingliquid crystal therethrough.

[0083] On the other hand, a transmissive substrate base material 5 b′made of glass and having a large area as shown in FIG. 12 is preparedbesides the transmissive substrate base material 5 a′ for an elementsubstrate base material 3 a′. Four liquid crystal panel regions R areset on the surface of the transmissive substrate base material 5 b′, anda color filter 9 and opposite electrodes 8 are formed in each of theliquid crystal panel regions R, whereby an opposite substrate basematerial 3 b′ having a large area is formed.

[0084] Next, the element substrate base material 3 a′ shown in FIG. 11and the opposite substrate base material 3 b′ shown in FIG. 12 arebonded so that the liquid crystal panel regions R in the respective basematerials precisely align with each other, thereby forming an emptypanel having a large area. Usually, alignment marks are formed atappropriate positions of the element substrate base material 3 a′ andthe opposite substrate base material 3 b′, and the bonding is performedwith reference to the marks.

[0085] A cutting line, what is called a scribe line, is formed at apredetermined position around each of the liquid crystal panel regionsR. Either the element substrate base material 3 a′ or the oppositesubstrate base material 3 b′ is cut at the liquid crystal inlets 2 aalong the scribe lines, so that the liquid crystal inlets 2 a areexposed to the outside. Liquid crystal is filled into the respectiveliquid crystal panel regions R through the liquid crystal inlets 2 a.After the completion of filling, the liquid crystal inlets 2 a aresealed. Thereby, a large-area panel filled with liquid crystal isfabricated. After that, individual liquid crystal panels are cut out oneby one by cutting the large-area panel along the scribe lines formedaround the respective liquid crystal panel regions R, and one liquidcrystal panel shown in FIG. 10 is completed.

[0086] As described with reference to FIG. 8, the offset between theblack matrix opening portion K and the pixel electrode 6 can beprecisely detected in a short time by using the position check marks 15a and 15 b in the liquid crystal device of the present invention. Thedetection step may be carried out for each of the liquid crystal devices1 that are finally obtained (see FIG. 10), in the state in which thelarge-area panel is empty, or in the state in which the large-area panelis filled with liquid crystal before scribing. When defectives arepreviously selected by subjecting the large-area panel, which is emptyor filled with liquid crystal, to a position check, it is possible toomit the subsequent processes for the defectives, and to thereby improveoperation efficiency.

[0087] (Fourth Embodiment)

[0088]FIG. 13 shows the principal part of another embodiment of a liquidcrystal device according to claim 5, in particular, one of a pluralityof pixel electrodes formed on the surface of an element substrate andthe surroundings thereof. The same numerals given to constituents of anelement substrate 23 a as in FIG. 8 denote the same constituents, and adescription thereof will be omitted.

[0089] The element substrate 23 a in this embodiment is different fromthe element substrate 3 a shown in FIG. 8 in that a position check mark35 is shaped like a frame on the entire outer periphery of a pixelelectrode 6, while a pair of position check marks 15 a and 15 b areformed at the opposite corners of the pixel electrode 6 on the elementsubstrate 3 a. This position check mark 35 can also be formedsimultaneously with the formation of a second electrode 14 of a MIMelement 11.

[0090] Since the position check mark 35 is formed on the entireperiphery of the pixel electrode 6 in this embodiment, when the offsetbetween a black matrix opening portion K and the pixel electrode 6 ischecked by using the position check mark 35, the check can be made atany point on the mark 35. As a result, a more precise judgement ispossible.

[0091] (Fifth Embodiment)

[0092]FIGS. 14 and 15 show the principal part of a further embodiment ofthe liquid crystal device according to claim 5. In particular, FIG. 14shows one of a plurality of pixel electrodes formed on the surface of anelement substrate, and the surroundings thereof, and FIG. 15 shows thesectional structure taken along line Z-Z in FIG. 14.

[0093] In this embodiment, the present invention is applied to a liquidcrystal device including MIM elements having what is called aback-to-back structure. Regarding the MIM elements having theback-to-back structure, a pair of MIM elements 11A and 11B are connectedin series in an electrically inverse relationship, as shown in FIG. 14,thereby stabilizing the switching characteristics of the MIM elements.These MIM elements 11A and 11B have a layered structure including afirst electrode 12, an insulating layer 13, and a second electrode 14,respectively.

[0094] In the liquid crystal device using this type of MIM elementhaving the back-to-back structure, in order to improve the adhesion ofthe MIM elements 11A and 11B, an underlayer 22 having a uniformthickness and made of tantalum oxide (TaOX) is formed in most cases onthe surface of a transmissive substrate 5 a of an element substrate side33 a in advance to the formation of the first electrodes 12 of the MIMelements 11A and 11B. When such an underlayer 22 remains between thepixel electrode 6 and the transmissive substrate 5 a, the lighttransmittance at the pixel electrode 6 decreases and a display area ofthe liquid crystal device becomes dark.

[0095] In order to solve this problem, it is effective to carry out, ina series of steps of manufacturing the element substrate 33 a, the stepsof removing the underlayer 22, which exists in a predetermined area forforming the pixel electrode 6 therein, after forming the secondelectrodes 14 of the MIM elements 11A and 11B and before laying thepixel electrode 6 at the leading end of the second electrode 14, andthen forming the pixel electrode 6. The region denoted by the numeral Jin FIG. 15 represents the outer peripheral line of a removed area incase when the underlayer 22 is removed at a predetermined area, namely,the peripheral line of the underlayer 22.

[0096] In this embodiment, when a part of the underlayer 22, which isformed on the transmissive substrate 5 a to improve the adhesion of theMIM elements 11A and 11B, corresponding to the pixel electrode 6 isremoved, the size of the removed area is set equal to that of the blackmatrix opening portion K. The peripheral line J of the underlayer 22that is caused to appear by removing the underlayer 22 serves as aposition check mark for use in checking the offset between the elementsubstrate 33 a and an opposite substrate 33 b.

[0097] Since the peripheral line J of the removed area of the underlayer22 is always formed in a fixed positional relationship to the pixelelectrode 6, it is possible to precisely confirm whether the oppositesubstrate 33 b and the element substrate 33 a are offset from eachother, by comparing the peripheral line J and the black matrix openingportion K. Moreover, since TaOX serving as the material of theunderlayer 22 has a higher light-shielding ability than that of ITO forforming the pixel electrode 6, the peripheral line J and the blackmatrix opening portion K can be even more easily seen than the case inwhich the peripheral edge of the black matrix opening portion K iscompared with the peripheral edge of the pixel electrode 6, andtherefore, the offset can be precisely detected in a short time.

[0098] (Modification)

[0099] While the liquid crystal device according to claim 5 has beendescribed above in its preferred embodiments, the present invention isnot limited to those embodiments. Various modifications may be madewithin the scope of the present invention as defined in the claims.

[0100] For example, the position check mark is not always limited to themark having two branch portions as shown in FIG. 8, and it may have nobranch portion. Furthermore, the material of the position check mark isnot limited to the same material as that of the second electrode of theMIM element, and it may be the same as the material of the firstelectrode of the MIM element, or a material that is not related to theMIM element. However, the use of the same material as that of the MIMelement is advantageous because the position check mark can besimultaneously formed in a predetermined step of forming the MIMelement.

[0101] Furthermore, the second electrode of the MIM element and thepixel electrode may be integrally formed by making the second electrodeof, for example, ITO, being the same material as that of the pixelelectrode. This allows the step of forming the second electrode to beomitted. In this case, the position check mark is made of the samematerial as that of the first electrode.

[0102] A reference mark on the opposite substrate side to be comparedwith the position check mark formed on the element substrate side is notlimited to the black matrix opening portion. For example, the peripherallines of respective color dots of R, G, and B in the color filter formedon the opposite substrate may be used as the subject of comparison.

[0103] The nonlinear element is not limited to the MIM element. Whilethe element substrate base material and opposite substrate base materialhaving a large area for four liquid crystal panels are used in the abovedescription, of course, it may be possible to use substrate basematerials having such a size that a plurality of, less or more thanfour, liquid crystal panels are manufactured.

[0104] While the liquid crystal device shown in FIG. 10 is what iscalled a COG (Chip On Glass) liquid crystal device having a structure inwhich a liquid crystal driving IC is directly mounted on a transmissivesubstrate, the present invention may be applied to liquid crystaldevices having other arbitrary structures, for example, a liquid crystaldevice using a TAB (Tape Automated Bonding) method.

[0105] (Sixth Embodiment)

[0106]FIG. 16 shows a further embodiment of the liquid crystal deviceaccording to claims 1 and 5, and in particular, shows individual pixelson a large-area element substrate base material 43 a′ in an enlargedplan view. Referring to this figure, one pixel is mainly composed of onepixel electrode 6. An underlayer 22 having a uniform thickness is formedon the entire surface of the element substrate base material 43 a′, anda plurality of linear gate electrode lines 52 are formed thereon inparallel with one another. A current carrying pattern 57 is formed forthe gate electrode lines 52. This current carrying pattern 57 supplieselectric current to the gate electrode lines 52.

[0107] A gate electrode line 52 and a pixel electrode 6 are connected toeach other via a TFT element 55 serving as an active element, as shownin FIG. 17. This TFT element 55 is formed, as shown in FIG. 18, bylaying on the underlayer 22 the following layers one on top of another,namely, a gate electrode 52 a, an anodized film 53 serving as a gateinsulating film, a nitride film 59 serving as another gate insulatingfilm, an a-Si (amorphous silicon) film 61 serving as a channel-partintrinsic semiconductor film, a N⁺a-Si (doped amorphous silicon) film 62serving as a contact-part semiconductor film, and a channel-partprotective nitride film 63.

[0108] Referring to FIG. 16, a plurality of linear source electrodelines 64 are formed in parallel on the surface of the element substratebase material 43 a′ in such a positional relationship that theyintersect the gate electrode lines 52. These source electrode lines 64each are laid on one side (left side in FIG. 17) of the N⁺a-Si film 62,as shown in FIGS. 17 and 18. On the other side (i.e., right side in FIG.17) of the N⁺a-Si film 62, the pixel electrode 6 is overlaid.

[0109] The TFT element 55 having the structure mentioned above is formedas follows, for example. Namely, referring to FIG. 19, first, theelement substrate base material 43 a′ made of glass or the like isprepared, and Ta₂O₅ or the like having a uniform thickness is formedthereon by sputtering or the like, thereby forming the underlayer 22.

[0110] Next, Ta is patterned on the underlayer 22 by a known patterningtechnique, for example, lithography to form the plural linear gateelectrode lines 52, the gate electrodes 52 a for the TFT element thatproject from the gate electrode lines 52, and the current carryingpattern 57 for linking the gate electrode lines 52 of the respectiveliquid crystal device portions.

[0111] After that, an anodizing process is carried out by dipping theelement substrate base material 43 a′ in an electrolyte, namely, ananodizing solution, and applying a predetermined voltage to the currentcarrying pattern 57. Thereby, the anodized film 53 is formed on the gateelectrodes 52 a and other patterns.

[0112] Next, referring to FIG. 18, the gate protective film 59 is formedon each of the anodized films 53 formed as mentioned above by patterningSi₃N₄ by CVD for example. Furthermore, a-Si is uniformly overlaid, andN⁺a-Si is further uniformly overlaid thereon. The contact-partsemiconductor films 62 are formed by patterning N⁺a-Si by photoetchingor the like, and the channel-part intrinsic semiconductor films 61 areformed by patterning a-Si.

[0113] After that, the channel-part protective films 63 are formed bypatterning Si₃N₄ by using a known patterning technique, and the pixelelectrodes 6 are formed in a matrix by patterning ITO (Indium Tin Oxide)in a predetermined dot-like form so as to partly overlie on the N⁺a-Sifilms 62. Furthermore, the source electrode lines 64 are formed inparallel by patterning Al (aluminum) so as to partly overlie on theN⁺a-Si films 62.

[0114] Then, an alignment film having a uniform thickness is formed onthe surface of the substrate, and is subjected to uniaxial alignmenttreatment, for example, rubbing treatment. Furthermore, a ring-shapedsealing member is formed by screen-printing or the like. Thereby, thepredetermined process for the element substrate base material iscompleted. After that, a large-area panel structure is formed byoverlaying the opposite substrate base material, which is preparedseparately from the element substrate base material, on the elementsubstrate base material, and liquid crystal is sealed into the liquidcrystal device parts of the respective panel structure. A plurality ofliquid crystal panels each for one liquid crystal device are formed bycutting the panel structure, and a polarizer, a liquid crystal drivingIC and the like are mounted on each of the liquid crystal panels,whereby a plurality of desired liquid crystal devices are manufactured.

[0115] In this embodiment, when the N⁺a-Si films 62 are formed aselement-side electrodes by photoetching or the like, they are shapedlike a pattern extending along the edge of one side 6 a of the pixelelectrode 6, as shown in FIG. 16. Since the N⁺a-Si film 62 has a higherlight-shielding ability than that of the pixel electrode 6, it canfunction as a mark having a high light-shielding ability that causes theedge of the pixel electrode 6 to visually stand out. In this embodiment,a N⁺a-Si film 62 a is also formed at the corner of the pixel electrode 6that is diagonally opposite the corner where the TFT element 55 isprovided. This N⁺a-Si film 62 a mainly functions as a mark having highlight-shielding ability that causes the edge of the pixel electrode 6 tovisually stand out. As mentioned above, according to this embodiment,since the N⁺a-Si film 62 is formed in a pattern along the edge of oneside 6 a of the pixel electrode 6, it is possible to prevent etchantfrom entering between the N⁺a-Si film 62 and the ITO film in forming thepixel electrode 6 by etching the ITO film, and to thereby prevent a wirebreak therebetween.

[0116] Since the N⁺a-Si films 62 and 62 a having a higherlight-shielding ability than that of the pixel electrode 6 are formedcorresponding to the opposite corners of the pixel electrode 6, when theopposite substrate base material (see FIG. 12) is bonded to the elementsubstrate base material 43 a′, it is possible to easily and preciselydetermine whether or not the element substrate base material and theopposite substrate base material are in a proper positional relationshipby visually comparing the mark formed on the element substrate basematerial, for example, the periphery of the black matrix, and theaforementioned N⁺a-Si films 62 and 62 a.

[0117] While the amorphous silicon TFT element is described as anexample of the nonlinear element in this embodiment, the presentinvention may be also applied to a polysilicon TFT element. A film,which has a higher light-shielding ability than that of the pixelelectrode, for constituting the TFT element is formed so that itoverlaps with at least the opposite corners of the pixel electrode in aplane manner.

[0118] Industrial Applicability

[0119] The liquid crystal device of the present invention can besuitably used as a display part of a portable telephone, a display of aportable computer, and the like. The liquid crystal device manufacturingmethod of the present invention can be utilized as a technique ofreducing as many defectives as possible in manufacturing liquid crystaldevices. The electronic apparatus of the present invention can beapplied in a broad market as consumer and business equipment, such as aportable telephone and a computer.

1. A liquid crystal device having a plurality of pixel electrodes, and anonlinear element including an element-side electrode electricallyconnected to said pixel electrodes, wherein said element-side electrodeis shaped in a pattern formed along the edge of said pixel electrode. 2.The liquid crystal device according to claim 1, wherein saidelement-side electrode is shaped like a ring-shaped frame along theentire peripheral edge of said pixel electrode.
 3. The liquid crystaldevice according to claim 1 or 2, wherein the outer dimensions of saidelement-side electrode is larger than that of said pixel electrode. 4.An electronic apparatus, comprising: a liquid crystal device accordingto claim 1; and a control section for controlling the operation of saidliquid crystal device.
 5. A liquid crystal device having an elementsubstrate having a nonlinear element and a pixel electrode on asubstrate, and an opposite substrate placed opposed to said elementsubstrate, said liquid crystal device comprising a mark that overlapswith at least a part of the peripheral edge of said pixel electrode in aplane manner and has a higher light-shielding ability than that of saidpixel electrode.
 6. The liquid crystal device according to claim 5,wherein said mark is disposed at least at two positions at the oppositecorners of said pixel electrode, and has two branch portions extendingalong two sides adjoining the corners.
 7. The liquid crystal deviceaccording to claim 5, wherein said mark is shaped like a frame formedalong the entire peripheral edge of said pixel electrode.
 8. The liquidcrystal device according to claim 5, wherein said element substrate hasan underlayer between said substrate and said nonlinear element, animage area portion of said underlayer corresponding to said pixelelectrode is removed from said substrate, and the peripheral edge ofsaid pixel area portion of said underlayer is used as said mask.
 9. Theliquid crystal device according to at least one of claims 5 to 8,wherein said nonlinear element is a two-terminal type nonlinear elementhaving a first electrode, an oxide film laid on said first electrode,and a second electrode laid on said oxide film, and said mark is made ofthe same material as that of said first electrode or said secondelectrode of said two-terminal type nonlinear element.
 10. The liquidcrystal device according to at least one of claims 5 to 8, wherein saidnonlinear element is a thin-film transistor element, and said mark ismade of the material of one of said films for constituting saidthin-film transistor element, said film having a higher light-shieldingability than that of said pixel electrode.
 11. The liquid crystal deviceaccording to at least one of claims 5 to 10, wherein said oppositesubstrate has a black matrix for divisionally forming an opening portioncorresponding to a pixel, and said mark is used to confirm the positionwith respect to the peripheral edge of said opening portion of saidblack matrix.
 12. A liquid crystal device manufacturing method havingthe step of bonding an element substrate with a nonlinear element and apixel electrode formed on a substrate, and an opposite substrate placedopposed to said element substrate, comprising the steps of: forming onsaid element substrate a mark having a higher light-shielding abilitythan that of said pixel electrode such as to overlap with at least apart of the peripheral edge of said pixel electrode in a plane manner;and confirming with reference to said mark whether said elementsubstrate and said opposite substrate are bonded in a proper positionalrelationship.
 13. The liquid crystal device manufacturing methodaccording to claim 11, wherein said opposite substrate has a blackmatrix for divisionally forming an opening portion corresponding to apixel, and positional comparison is made between said mark and theperipheral edge of said opening portion of said black matrix.
 14. Theliquid crystal device manufacturing method according to claim 11,wherein said opposite substrate has a color filter including color dotsof a plurality of colors, and positional comparison is made between saidmark and the peripheral edges of said color dots of said color filter.